The present invention generally relates to balloon catheters and, more particularly, to a rapid exchange stent delivery balloon catheter.
The use of balloon catheters to treat strictures, stenoses, or narrowings within various parts of the human body is well known. In a typical procedure, for example to dilate a stenosis in the coronary arteries, a relatively large guiding catheter is inserted into the patient""s arterial system in the groin. The guiding catheter is then advanced through the arteries to a location near the patient""s heart. A small wire guide is then inserted into the guiding catheter and advanced to the distal end of the guiding catheter, at which point it is steered to extend through the stenosis in the coronary arteries. A balloon catheter is then advanced over the wire guide until the deflated balloon lies across the stenosis. A working fluid is then pumped through the balloon catheter, thereby inflating the balloon and dilating the passage through the stenosis.
After such a dilitation procedure, it is often found desirable to install a stent in the area of the stenosis in order to ensure patency of the lumen in the artery. Such a stent is delivered on the end of an inflatable balloon stent delivery catheter. The deformable stent is wrapped around the deflated balloon of the catheter and the catheter is inserted into the patient""s body to the location of the stenosis. When the balloon of the stent delivery catheter is inflated, the stent is plastically deformed to an expanded condition, the balloon is deflated, and the stent delivery catheter is withdrawn, leaving the expanded stent in place to preserve the patency of the arterial lumen. Because such stent delivery catheters have wire guide lumens which extend the entire length of the catheter, they cannot be inserted to the stenosis site over the wire guide which is used to insert the balloon angioplasty catheter (such wire guides are too short). Therefore, after the stenosis has been dilated, the balloon angioplasty catheter and wire guide are removed from the guiding catheter and a second wire guide, or exchange wire guide, is inserted through the guiding catheter and steered to the stenosis location. The exchange wire guide is more than twice as long as the stent delivery catheter because it is necessary that the wire guide protrude from the patient""s body by a length greater than the length of the stent delivery catheter. This allows the exchange wire guide to be held steady with the physician""s hand while the stent delivery catheter is advanced over the exchange wire guide. Once the distal end of the stent delivery catheter has been placed within the area of the dilated stenosis, the balloon of the stent delivery catheter may be inflated, thereby plastically deforming the stent in the region of the dilated stenosis. The balloon of the stent delivery catheter is then deflated, allowing the stent delivery catheter to be withdrawn, leaving the expanded stent in place. The exchange wire guide and the guiding catheter are then withdrawn, thereby completing the operation.
In situations where physicians find it desirable to install a stent after the balloon angioplasty procedure, the need to replace the wire guide with an exchange wire guide is a cumbersome and undesirable requirement. This is due to the fact that it is necessary that the second exchange wire guide be steered through the patient""s arterial system until it reaches the location of the original stenosis. Furthermore, the great length of the exchange wire guide which extends outside of the patient""s body must sometimes extend beyond the sterile area of the surgical table.
There is therefore a need in the prior art for a stent delivery catheter which may be used with the same wire guide that is used to steer the balloon angioplasty catheter. The present invention is directed toward meeting this need.
The present invention relates to a rapid exchange stent delivery balloon catheter which allows exchange from a balloon angioplasty catheter to a stent delivery catheter without the need to replace the angioplasty catheter wire guide with an exchange-length wire guide before exchanging the catheters. The stent delivery catheter of the present invention includes a relatively short wire guide shaft which is bonded to the catheter shaft only at a location distal to the inflation lumen.
In one form of the invention, a rapid exchange stent delivery balloon catheter is disclosed, comprising a catheter shaft defining an inflation lumen, the inflation lumen having a proximal end and a distal end; an inflatable balloon having a proximal end and a distal end; a wire guide shaft defining a wire guide lumen, the wire guide shaft having a proximal end and a distal end; and a catheter tip having a proximal end and a distal end; wherein the distal end of the inflation lumen opens into and is in fluid communication with an interior of the inflatable balloon, the distal end of the inflatable balloon is sealed by the proximal end of the catheter tip, and the wire guide shaft is coupled to the catheter tip, said coupling being completely distal of the distal end of the inflatable balloon.
In another form of the invention, a balloon catheter stent configuration is disclosed comprising a catheter shaft defining an inflation lumen having a proximal end and a distal end; an inflatable balloon having a proximal end and a distal end; a wire guide shaft defining a wire guide lumen, said wire guide shaft having a proximal end and a distal end; a catheter tip having a proximal end and a distal end; and a stent mounted on and surrounding said inflatable balloon and wire guide shaft; wherein the distal end of the inflation lumen opens into and is in fluid communication with the inflatable balloon, the distal end of the inflatable balloon is sealed by the proximal end of the catheter tip, and the wire guide shaft is coupled to the catheter tip, said coupling being completely distal of the distal end of the inflatable balloon.